<?php

/**
 * @file
 *
 * MultiLink Filter module for Drupal 7.
 * Support: Commercial support and customization is available from www.netgenius.co.uk
 * Contact: www.netgenius.co.uk/contact or email drupal at netgenius.co.uk
 */

function multilink_filter_filter_info() {

  $filters['multilink_filter'] = array(
    'title' => 'MultiLink',
    'description' => t('Creates links to nodes, selecting a translated version if available.'),
    'process callback'  => '_multilink_filter_process',
    'settings callback' => '_multilink_filter_settings',
    'tips callback' => '_multilink_filter_process_tips',
    //'default settings' => '_multilink_filter_default_settings',

    // We must disallow caching by default. Drupal caches by $node->language, not current selected language.
    'cache' => module_exists('plc'),
    //'cache' => FALSE,
  );

  return $filters;
}

/*
 * Implement hook_filter_tips().
 */
function _multilink_filter_process_tips($delta, $format, $long = FALSE) {

  // Get $mod_name, and $mod_prefix;
  extract(_multilink_get_ids($format));
  if (_multilink_setting($mod_prefix, 'enable_MultiLink')) {
    $tvars = array('%all' => t('all'), '%other' => t('other'));
    $short_help = t(_multilink_setting($mod_prefix, 'short_help'), $tvars);
    $long_help = $short_help;

    return t($long? $long_help : $short_help, $tvars);
  }
}

/*
 * Wrapper for _multilink_getnode adding handling for invalid nid and access control.
 */
function _multilink_filter_getnode($nid) {

  $link = _multilink_getnode($nid);
  if (!$link) {
    // $nid was invalid.
    $msg = t('Referenced node @nid does not exist', array('@nid' => $nid));
    watchdog('multilink', $msg, array(), WATCHDOG_WARNING);
    @$link->nid = $nid;
    $link->title = t('Not found');
  }
  // Security - check access to the node before allowing use of cached title.
  elseif (!($link->access || node_access('view', node_load($link->nid)))) {
    $link->title = t('Not allowed');
  }

  return $link;
}

/*
 * Process MultiLink links.
 */
function _multilink_filter_multilink_process($matches) {
  // matches will be: Array ( [0] => [123:title-text] [1] => 123 [2] => title-text )
  // Get link path and title.
  $link = _multilink_filter_getnode($matches[1]);
  if ($matches[2] == '$')  $matches[2] = $link->title;
  // Build target link.
  $options = array('external' => 1, 'attributes' => array('title' => $link->title));
  $result = l($matches[2], multilink_url('node/' . $link->nid), $options);
  ////multilink_set_message('multilink process: ' . (print_r($result, 1)), 'warning');
  return $result;
}

/*
 * Process other types of link.
 */
function _multilink_filter_others_process($matches) {

  // Are we processing a link?
  if (count($matches) == 5) {
    // URL-based - Markdown, HTML anchor tag, etc.
    // matches: 0:full, 1:pre-path, 2:path-without-nid , 3:nid, 4:post-path.
    // To keep things simple regexp is such that , $matches[2] will be 'node' or '/node'
    $link = _multilink_filter_getnode($matches[3]);
    $path = trim($matches[2], '/') . '/' . $link->nid;
    $result = ($link->nid)? $matches[1] . multilink_url($path) . $matches[4] : $matches[0];
  }
  // Otherwise we're processing a tag.
  elseif (count($matches) == 4) {
    // Pathfilter, InsertNode, etc.
    // matches: 0:full, 1:pre-nid, 2:nid, 3:post-nid.
    $link = _multilink_filter_getnode($matches[2]);
    $result = ($link->nid)? $matches[1] . $link->nid . $matches[3] : $matches[0];
  }
  else {
    $result = $matches[0];
  }
  ////multilink_set_message('others process: <br>' . htmlentities(print_r($matches, 1)), 'warning');
  return $result;
}

/*
 * Implement hook_filter().
 */
function _multilink_filter_process($text, $filter, $format, $langcode, $cache, $cache_id) {

  // Get $mod_name, $mod_id and $mod_prefix;
  extract(_multilink_get_ids($format));

  $patterns = _multilink_filter_enabled_patterns($format);
  if (!empty($patterns)) {

    // Handle an important special case:
    // If this page is cacheable, we need different processing because our generated links will end up in the cached page.
    // @todo Prevent caching when generated links are different from those needed for a generic cached page.
    if (drupal_page_is_cacheable()) {
      $GLOBALS['multilink_pref_languages'] = array($GLOBALS['language']->language, $langcode);
      //multilink_set_message(sprintf('pref: %s', print_r($GLOBALS['multilink_pref_languages'], 1)));
    }

    // Need to set a global so that callbacks can use the correct value for 'absolute'.
    // @todo Is there a cleaner way? Problem is that setting depends on current format.
    $GLOBALS['multilink_absolute'] = _multilink_setting($mod_prefix, 'absolute');

    if (isset($patterns['MultiLink'])) {
      $pattern = $patterns['MultiLink'][1];
      $text = preg_replace_callback($pattern, '_multilink_filter_multilink_process', $text);
      unset($patterns['MultiLink']);
    }
    foreach ($patterns as $name => $test) {
      ////multilink_set_message($name . ' - check: ' . htmlspecialchars($test[0]) . ' regexp: ' . htmlspecialchars($test[1]), 'warning');
      if (!$test[0] || strpos($text, $test[0]) !== FALSE) {
        $text = preg_replace_callback($test[1], '_multilink_filter_others_process', $text);
      }
    }
    // Unset language preferences override which may have been set above.
    unset($GLOBALS['multilink_pref_languages']);
  }
  return $text;
}

/*
 * Define patterns to support other types of links (formats used by other input filters modules.)
 */
function _multilink_filter_link_formats($format) {
  // Get $mod_name, $mod_id and $mod_prefix;
  extract(_multilink_get_ids($format));

  // Add MultiLink formats
  $formats['MultiLink'] = array(FALSE, _multilink_setting($mod_prefix, 'pattern'));

  // This is a list of filter modules whose format we support.
  // Uses: module_filename => array(Module_Name, test-string, regexp-pattern
  // Regexp must define either 3 or 4 groups.
  $modules = array(
    // Linodef - http://drupal.org/project/linodef
    'lindodef' => array('Linodef', '[#', '/(\[#)(\d+)(.*?\])/'),
    // Path Filter - http://drupal.org/project/pathfilter
    'pathfilter' => array('Path Filter', 'internal:node', '/(["\']internal:node\/)(\d+)(.*?["\'])/'),
    // Pathologic - http://drupal.org/project/pathologic (offers Path Filter compatibility)
    'pathologic' => array('Pathologic (Path Filter)', 'internal:node', '/(["\']internal:node\/)(\d+)(.*?["\'])/'),
    // Link node - http://drupal.org/project/link_node (format is identical to InsertNode.)
    'link_node' => array('Link node', '[node:', '/(\[node:)(\d+)(.*?\])/'),
    // InsertNode - http://drupal.org/project/InsertNode (format is identical to Link node.)
    'InsertNode' => array('InsertNode', '[node:', '/(\[node:)(\d+)(.*?\])/'),
    // Markdown - http://drupal.org/project/markdown
    'markdown' => array('Markdown', '(/node/', '/(\[.*?\]\()(\/node\/)(\d+)(.*?\))/'),
  );

  // Build an array of allowed module-formats...
  if (_multilink_setting($mod_prefix, 'format_test')) {
    // Test-mode - allow all module-formats.
    foreach ($modules as $module) {
      $formats[$module[0]] = array($module[1], $module[2]);
    }
  }
  else {
    // Scan the filter to see which supported modules are enabled in the filter.
    foreach (filter_list_format($format->format) as $filter) {
      $module_id = $filter->module;
      if (isset($modules[$module_id])) {
        $module = $modules[$module_id];
        $formats[$module[0]] = array($module[1], $module[2]);
      }
    }
  }

  // Add Generic HTML format to the end.
  // Note: For simplicity, we only allow for relative paths such as /node/123.
  $formats['Generic HTML'] = array('/node/', '/(<a .*?href=["\']?)(\/node\/)(\d+)(.*?>.*?<\/a>)/');

  return $formats;
}

/*
 * Get patterns to support other types of links.
 */
function _multilink_filter_enabled_patterns($format) {
  static $patterns;

  $format_id = $format->format;
  if (!isset($patterns[$format_id])) {
    // Get $mod_name, $mod_id and $mod_prefix;
    extract(_multilink_get_ids($format));

    $patterns[$format_id] = array();
    // Get available link formats.
    $link_formats = _multilink_filter_link_formats($format);
    // Add each enabled link format to the result.
    foreach ($link_formats as $name => $settings) {
      $key = 'enable_' . str_replace(' ', '_', $name);
      if (_multilink_setting($mod_prefix, $key)) {
        $patterns[$format_id][$name] = $settings;
      }
    }
  }
  ////multilink_set_message($format . ': enabled formats: ' . htmlspecialchars(print_r($patterns[$format], 1)), 'error');
  return $patterns[$format_id];
}

function _multilink_filter_default_settings() {
  $defaults = array(
    'pattern' => '/\[(\d+): ?(.+?)\]/',
    'short_help' => 'Enter node links as <em>[1234:text]</em> '
                  . 'where <em>1234</em> is a node number and <em>text</em> is what should be displayed '
                  . 'or <em>$</em> to display the node\'s title.',
    'enable_MultiLink' => TRUE,
  );
  return $defaults;
}

/*
 * Custom submit function .
 * We have a specific method for storing configuration values, which was convenient under D6.
 * Due to how the D7 filter settings form saves settings values, we need to add use own submit function.
 * @todo Consider converting our method for storing configuration (requires changes elsewhere.)
 */
function _multilink_filter_settings_submit($form, $form_state) {
  // Get $format
  $format = $form['#format']->format;

  // Get $mod_name, $mod_id and $mod_prefix;
  extract(_multilink_get_ids($format));
  $len = drupal_strlen($mod_prefix);

  // Loop through form_state values, saving ours...
  $values = options_array_flatten($form_state['values']);
  foreach ($values as $name => $value) {
    // If the $name starts with our $mod_prefix...
    if (drupal_substr($name, 0, $len ) == $mod_prefix) {
      // Get $key (name without prefix.)
      $key = drupal_substr($name, $len);
      // If value has changed, save it.
      if ($value != _multilink_setting($mod_prefix, $key)) {
        variable_del($name, $value);
        // If value is non-default, save it.
        if ($value != _multilink_setting($mod_prefix, $key)) {
          variable_set($name, $value);
        }
      }
    }
  }
}

/*
 * Build and return the settings form.
 */
function _multilink_filter_settings(&$form, &$settings_state, $filter, $format, $defaults) {

  // Add our custom submit function, plus the standard submit.
  $form['#submit'][] = 'filter_admin_format_form_submit';
  $form['#submit'][] = '_multilink_filter_settings_submit';

  // Get $mod_name, $mod_id and $mod_prefix;
  extract(_multilink_get_ids($format));
  $shared = _multilink_setting($mod_prefix, 'shared');

  // Get default settings.
  //$filter->settings += $defaults;

  //require_once(dirname(__FILE__) . '/help.html');
  global $language;
  $textsize = 30;

  // Some settings should be reset to default if set blank in the form:
  $keys = array('pattern', 'short_help');
  foreach ($keys as $key) {
    if (!_multilink_setting($mod_prefix, $key)) {
      variable_del($mod_prefix . $key);
    }
  }

  if ($shared) {
    // Show a message.
    $settings['#value'] = sprintf('<strong>%s</em></strong>', t('NOTE: Using shared settings.'));
  }

  // Create collapsible section for this module in the filters configuration form.
  $section =& $settings[$mod_id];

  $section =& $settings[$mod_id];
  $section = array(
    '#type' => 'vertical_tabs',
  );

  $fieldset =& $section['main'];
  $fieldset = array(
    '#type' => 'fieldset',
    '#title' => t('Options'),
    //'#description' => t('This section defines general options.'),
  );

  $key = 'absolute';
  $fieldset[$mod_prefix . $key] = array(
    '#type' => 'checkbox',
    '#title' => t('Absolute urls'),
    '#default_value' => _multilink_setting($mod_prefix, $key),
    '#description' => t('If set, links will be generated with absolute urls, i.e: http://example.com/node/1'),
  );

  $key = 'short_help';
  $fieldset[$mod_prefix . $key] = array(
    '#type' => 'textarea',
    '#title' => t('User help'),
    '#rows' => 2,
    '#default_value' => _multilink_setting($mod_prefix, $key),
    '#description' => t('Filter-help shown to the user. This text is passed through t().  Blank to reset to default value.'),
  );

  /*
  $section['help'] = array(
    '#type' => 'markup',
    '#value' => '<p>Help goes here.</p>',
  );
  */


  // --- Link formats ---
  $link_formats = array_keys(_multilink_filter_link_formats($format));
  $fieldset =& $section['link_formats'];
  $description = t('Choose what types of links/tags should be processed by MultiLink');
  $fieldset = array(
    '#type' => 'fieldset',
    '#title' => t('Link formats'),
    '#description' => sprintf('<strong><p>%s:</p></strong>', $description),
    '#collapsible' => TRUE, '#collapsed' => TRUE,
  );

  foreach ($link_formats as $name) {
    $key = 'enable_' . str_replace(' ', '_', $name);
    $fieldset[$mod_prefix . $key] = array(
      '#type' => 'checkbox',
      '#title' => $name,
      '#default_value' => _multilink_setting($mod_prefix, $key),
      '#description' => t('Process links/tags in %module format.', array('%module' => $name)),
    );
  }

  // --- Other format options ---
  $key = 'format_test';
  $fieldset[$mod_prefix . $key] = array(
    '#prefix' => '<hr />',
    '#type' => 'checkbox',
    '#title' => t('Test supported formats'),
    '#default_value' => _multilink_setting($mod_prefix, $key),
    '#description' => t('Allow all supported link-formats regardless of whether the corresponding filter modules are enabled. '
                      . 'Enabling this option will activate additional settings above (after saving.)'
                      ),
  );

/*
  $key = 'use_alias';
  $fieldset[$mod_prefix . $key] = array(
    '#type' => 'checkbox',
    '#title' => t('Convert to alias'),
    '#default_value' => _multilink_setting($mod_prefix, $key),
    '#description' => t('Should multlink convert /node/1234 to its alias (if available)?'),
  );
 */
  // --- Advanced settings ---
  $fieldset =& $section['advanced'];
  $fieldset = array(
    '#type' => 'fieldset',
    '#title' => t('Advanced'),
  );

  $key = 'shared';
  $fieldset[$mod_prefix . $key] = array(
    '#type' => 'checkbox',
    '#title' => t('Shared configuration'),
    '#default_value' => $shared,
    '#description' => t('Use the same configuration for all formats. If you change this, save and then check all configuration values.'),
  );

  $key = 'pattern';
  $fieldset[$mod_prefix . $key] = array(
    '#type' => 'textfield',
    '#title' => t('Pattern'),
    '#size' => 40,
    '#default_value' => _multilink_setting($mod_prefix, $key),
    '#description' => t('This pattern will be used to find %name links in the text.'
                      . ' You should not change the number of parenthesised groups in the expression.'
                      . ' Blank to reset default.', array('%name' => $mod_name)),
  );

  // Display caching options depending whether caching is possible (patch installed.)
  $fieldset =& $fieldset['cache'];
  $patched = defined('check_markup_language_patch_1');
  $msg = array('Patch for $func is not installed - output cannot be cached. See included README.txt',
               'Patch for $func is installed - output can be cached.',
              );
  $fieldset = array(
    '#type' => 'fieldset',
    '#title' => t('Output caching'),
    '#value' => t($msg[$patched], array('$func' => 'check_markup()')),
  );

  if ($patched) {
    $key = 'allow_cache';
    $fieldset[$mod_prefix . $key] = array(
      '#type' => 'checkbox',
      '#title' => t('Additional caching'),
      '#default_value' => _multilink_setting($mod_prefix, $key),
      '#description' => t('In addition to MultiLink\'s internal caching, allow Drupal to cache filtered output.'
                        . ' This should improve performance but displayed links may be out of date.'
                        . ' Even if this option is enabled, other filters may prevent caching.'
                        . ' If you change this option you must re-save the !settings afterwards.'
                        , array('!settings' => l(t('filter settings'), 'admin/settings/filter/' . $format))),
    );
  }

  return $settings;
}


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